Most indexing type industrial filtration machines sometimes use elaborate level sensing techniques to trigger the filter indexing mechanism. These elaborate systems are prone to failure because of the working environment of an industrial filter machine, which is usually very dirty and hostile toward sensitive equipment.
Most level sensing systems compare the inlet flow level to the outlet flow level. When the outlet flow level differs from the inlet level, it is because the filter media is loaded and restricting flow, and new media is needed.
Many of these level sensing systems use sensitive pneumatic circuits which are expensive, require considerable maintenance and oftentimes are too difficult for an average industrial worker to quickly diagnose.